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17 results on '"Hiroaki Ichihashi"'

1. Oral Iron Absorption of Ferric Citrate Hydrate and Hepcidin-25 in Hemodialysis Patients: A Prospective, Multicenter, Observational Riona-Oral Iron Absorption Trial

Author

Naohisa Tomosugi, Yoshitaka Koshino, Chie Ogawa, Kunimi Maeda, Noriaki Shimada, Kimio Tomita, Shoichiro Daimon, Tsutomu Shikano, Kazuyuki Ryu, Toru Takatani, Kazuya Sakamoto, Satonori Ueyama, Daisuke Nagasaku, Masato Nakamura, Shibun Ra, Masataka Nishimura, Chieko Takagi, Yoji Ishii, Noritoshi Kudo, Shinsuke Takechi, Takashi Ishizu, Takamoto Yanagawa, Masamichi Fukuda, Yutaka Nitta, Takayuki Yamaoka, Taku Saito, Suzuko Imayoshi, Momoyo Omata, Joji Oshima, Akira Onozaki, Hiroaki Ichihashi, Yasuhisa Matsushima, Hisahito Takae, Ryoichi Nakazawa, Koichi Ikeda, Masato Tsuboi, Keiko Konishi, Shouzaburo Kato, Maki Ooura, Masaki Koyama, Tsukasa Naganuma, Makoto Ogi, Shigeyuki Katayama, Toshiaki Okumura, Shigemi Kameda, and Sayuri Shirai

Subjects
oral iron absorption, ferric citrate hydrate, hemodialysis, hepcidin-25, iron shift, Biology (General), QH301-705.5, Chemistry, QD1-999
Abstract

Oral ferric citrate hydrate (FCH) is effective for iron deficiencies in hemodialysis patients; however, how iron balance in the body affects iron absorption in the intestinal tract remains unclear. This prospective observational study (Riona-Oral Iron Absorption Trial, R-OIAT, UMIN 000031406) was conducted at 42 hemodialysis centers in Japan, wherein 268 hemodialysis patients without inflammation were enrolled and treated with a fixed amount of FCH for 6 months. We assessed the predictive value of hepcidin-25 for iron absorption and iron shift between ferritin (FTN) and red blood cells (RBCs) following FCH therapy. Serum iron changes at 2 h (ΔFe2h) after FCH ingestion were evaluated as iron absorption. The primary outcome was the quantitative delineation of iron variables with respect to ΔFe2h, and the secondary outcome was the description of the predictors of the body’s iron balance. Generalized estimating equations (GEEs) were used to identify the determinants of iron absorption during each phase of FCH treatment. ΔFe2h increased when hepcidin-25 and TSAT decreased (−0.459, −0.643 to −0.276, p = 0.000; −0.648, −1.099 to −0.197, p = 0.005, respectively) in GEEs. FTN increased when RBCs decreased (−1.392, −1.749 to −1.035, p = 0.000) and hepcidin-25 increased (0.297, 0.239 to 0.355, p = 0.000). Limiting erythropoiesis to maintain hemoglobin levels induces RBC reduction in hemodialysis patients, resulting in increased hepcidin-25 and FTN levels. Hepcidin-25 production may prompt an iron shift from RBC iron to FTN iron, inhibiting iron absorption even with continued FCH intake.

Published
2023
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2. Model-Based Control for Dual-Fuel Engines

Author

Hiroaki Ichihashi, Yudai Yamasaki, Yoshitane Takashima, and Takahiro Sako

Subjects
dual-fuel engines, natural gas, control model, model-based control, combustion efficiency, Mechanical engineering and machinery, TJ1-1570
Abstract

The dual-fuel engine (DFE) has been focused on in order to improve its efficient use of natural gas. It has been reported that in DFE the combustion efficiency of the natural gas decreases at a low load. In an attempt to tackle this problem, it has been reported that a multi-stage diesel injection can improve the combustion efficiency of natural gas at a low load. The aim of this research is, therefore, to explain the mechanism for improving combustion efficiency with a multi-stage diesel injection and to develop a control model that predicts engines' combustion efficiency by multi-stage injection. Additionally, a controller was developed using the control model to improve the combustion efficiency by changing the diesel injection conditions. Experimental results show that the controller improves combustion efficiency. Furthermore, taking in to account the heat ratio of natural gas to diesel fuel in addition to combustion efficiency, it has been shown that it is possible to design a controller to leverage the advantage of DFE, which reduces the quantity of fossil fuels.

Published
2020
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3. Combustion and emission characteristics of multiple fuel injections on a dual fuel engine

Author

Hiroaki ICHIHASHI, Yudai YAMASAKI, and Shigehiko KANEKO

Subjects
internal combustion engine, dual fuel engine, natural gas, multiple fuel injection, exhaust emissons, Mechanical engineering and machinery, TJ1-1570, Engineering machinery, tools, and implements, TA213-215
Abstract

In DFE, it is known that emission and thermal efficiency improve by dividing the diesel injection into two at low load. However, the effect by dividing the diesel injection more than two, has not been investigated. Therefore, in this study, the effect of multiple diesel fuel injections on the combustion and exhaust emission characteristics of DFE using natural gas (city gas 13A) was investigated at low load in experiments. The experiments were conducted using a single-cylinder engine with a common rail injection system, varying the number of fuel injection and injection timing. The injection timing was set so that the interval of the injection becomes the parameter. The total injection quantity in one cycle was fixed and equally divided in multiple injections. By adapting double injection, the thermal efficiency did not improve against single injection. Total hydrocarbon (THC) emissions improved in some injection conditions, however increased in other injection conditions. NOx emission increased in narrow injection interval, but improved in wide injection interval. Furthermore, by adapting triple injection, THC emissions and the thermal efficiency improved against single and double injection. Also, NOx emission increased in narrow injection interval, but in wide injection interval NOx emissions did not increase against single injection.

Published
2019
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4. Oral Iron Absorption of Ferric Citrate in Haemodialysis Patients: The Prospective, Multicentre, Observational R-OIAT Study

Author

Naohisa Tomosugi, Yoshitaka Koshino, Chie Ogawa, Kunimi Maeda, Noriaki Shimada, Kimio Tomita, Shoichiro Daimon, Tsutomu Shikano, Kazuyuki Ryu, Toru Takatani, Kazuya Sakamoto, Satonori Ueyama, Daisuke Nagasaku, Masato Nakamura, Shibun Ra, Masataka Nishimura, Chieko Takagi, Yoji Ishii, Noritoshi Kudo, Shinsuke Takechi, Takashi Ishizu, Takamoto Yanagawa, Masamichi Fukuda, Yutaka Nitta, Takayuki Yamaoka, Taku Saito, Suzuko Imayoshi, Momoyo Omata, Joji Oshima, Akira Onozaki, Hiroaki Ichihashi, Yasuhisa Matsushima, Hisahito Takae, Ryoichi Nakazawa, Koichi Ikeda, Masato Tsuboi, Keiko Konishi, Shouzaburo Kato, Maki Ooura, Masaki Koyama, Tsukasa Naganuma, Makoto Ogi, Shigeyuki Katayama, Toshiaki Okumura, Shigemi Kameda, and Sayuri Shirai

Published
2022

6. Model-Based Control for Dual-Fuel Engines

Author

Takahiro Sako, Yoshitane Takashima, Yudai Yamasaki, and Hiroaki Ichihashi

Subjects
model-based control, lcsh:Mechanical engineering and machinery, 02 engineering and technology, Combustion, Industrial and Manufacturing Engineering, Automotive engineering, Diesel fuel, 0203 mechanical engineering, Natural gas, Control theory, Low load, lcsh:TJ1-1570, General Materials Science, business.industry, Mechanical Engineering, Fossil fuel, dual-fuel engines, 021001 nanoscience & nanotechnology, Model based control, Computer Science Applications, Dual (category theory), natural gas, 020303 mechanical engineering & transports, control model, Environmental science, 0210 nano-technology, business, combustion efficiency
Abstract

The dual-fuel engine (DFE) has been focused on in order to improve its efficient use of natural gas. It has been reported that in DFE the combustion efficiency of the natural gas decreases at a low load. In an attempt to tackle this problem, it has been reported that a multi-stage diesel injection can improve the combustion efficiency of natural gas at a low load. The aim of this research is, therefore, to explain the mechanism for improving combustion efficiency with a multi-stage diesel injection and to develop a control model that predicts engines' combustion efficiency by multi-stage injection. Additionally, a controller was developed using the control model to improve the combustion efficiency by changing the diesel injection conditions. Experimental results show that the controller improves combustion efficiency. Furthermore, taking in to account the heat ratio of natural gas to diesel fuel in addition to combustion efficiency, it has been shown that it is possible to design a controller to leverage the advantage of DFE, which reduces the quantity of fossil fuels.

Published
2020

7. Vascular mapping for the decision of hemodialysis access method: Case report

Author

Nakanobu Azuma, Tsukasa Sasaki, Hiroaki Ichihashi, Hiromasa Nakai, and Takashi Uchino

Subjects
medicine.medical_specialty, Percutaneous, medicine.medical_treatment, Clinical Decision-Making, 030232 urology & nephrology, Arteriovenous fistula, 030204 cardiovascular system & hematology, Transluminal Angioplasty, Upper Extremity, 03 medical and health sciences, Arteriovenous Shunt, Surgical, 0302 clinical medicine, Predictive Value of Tests, Renal Dialysis, Risk Factors, medicine, Humans, Ultrasonography, Interventional, Hemodialysis access, Aged, Catheter insertion, business.industry, Ultrasound, medicine.disease, Surgery, Contrast medium, Treatment Outcome, Nephrology, Female, Hemodialysis, business
Abstract

Preoperative ultrasound vascular mapping was performed to determine the surgical method for two cases where standard arteriovenous fistula was not possible. In case 1, the previous arteriovenous fistula of the left arm was occluded, and arteriovenous graft of the right arm was thrombosed after frequent percutaneous transluminal angioplasty. Contrast medium was contraindicated because of allergy. Using preoperative ultrasound vascular mapping, we were able to establish the appropriate surgical method. In case 2, hemodialysis was started by catheter insertion, and then access creation was planned. This case was treated with steroids due to a bullous pemphigoid disease and there was a high risk of infection, which precluded the use of synthetic grafts. There was also the possibility of delay in healing due to malnutrition. Therefore, appropriate surgical method was tailored by using preoperative ultrasound vascular mapping. Ultrasound vascular mapping was useful for determining the surgical creation of an appropriate access for facilitating hemodialysis cannulation.

Published
2018

10. Cut-Off Value of the Ankle-Brachial Pressure Index at Which the Accuracy of Brachial-Ankle Pulse Wave Velocity Measurement is Diminished

Author

Tomio Arai, Shin Ishimaru, Minoru Yambe, Hirofumi Tomiyama, Zaydun Gulinisa, Tsuneyuki Nagae, Akira Yamashina, Yutaka Koji, Hiroaki Ichihashi, and Koki Motobe

Subjects
Male, medicine.medical_specialty, Brachial Artery, Arteriosclerosis, Blood Pressure, Internal medicine, Ankle pulse, Humans, Medicine, Cutoff, cardiovascular diseases, Pulse wave velocity, Retrospective Studies, Sex Characteristics, Receiver operating characteristic, business.industry, Arterial stenosis, Patient Selection, Smoking, Wave velocity, Area under the curve, General Medicine, Middle Aged, Surgery, body regions, medicine.anatomical_structure, Cardiovascular Diseases, cardiovascular system, Cardiology, Female, Ankle, Cardiology and Cardiovascular Medicine, business
Abstract

Background The present study was conducted to establish the cutoff value of the ankle - brachial pressure index (ABI) at which the accuracy of brachial - ankle pulse wave velocity (baPWV) measurement is diminished Methods and Results The baPWV and ABI were measured in 1,361 patients with an atherosclerosis-related disease and 7,889 subjects without any atherosclerotic risk factors, in order to determine the percent difference of the brachial - ankle PWV (%baPWV), the angle of the rise of the anacrotic limb (%angle) and of the amplitude of the entire waveform (%amplitude) in both sides. The %angle and %amplitude were significantly higher in subjects whose %baPWV was ≥19% than in those subjects whose %baPWV was

Published
2005

11. Comparison of ankle-brachial pressure index and pulse wave velocity as markers of the presence of coronary artery disease in subjects with a high risk of atherosclerotic cardiovascular disease

Author

Tsuneyuki Nagae, Akira Yamashina, Shin Ishimaru, Hiroaki Ichihashi, Nobuhiro Tanaka, Hirofumi Tomiyama, Yutaka Koji, and Kenji Takazawa

Subjects
Male, medicine.medical_specialty, Multivariate analysis, Brachial Artery, Heart disease, Population, Blood Pressure, Coronary Artery Disease, Coronary Angiography, Logistic regression, Coronary artery disease, Japan, Heart Rate, Risk Factors, Internal medicine, medicine, Humans, cardiovascular diseases, Myocardial infarction, education, Pulse wave velocity, Aged, Aged, 80 and over, education.field_of_study, business.industry, Middle Aged, medicine.disease, Echocardiography, Doppler, Tibial Arteries, body regions, Quartile, Cardiovascular Diseases, Multivariate Analysis, cardiovascular system, Cardiology, Female, Ankle, Cardiology and Cardiovascular Medicine, business, Blood Flow Velocity, Follow-Up Studies, circulatory and respiratory physiology
Abstract

Recently, a measurement device that can simultaneously measure the ankle-brachial pressure index (ABI) and brachial-ankle pulse wave velocity (PWV) has become available. The present study compares the applicability of ABI and PWV as markers for predicting the prevalence of coronary artery disease (CAD) in subjects with a high risk of atherosclerotic cardiovascular disease. The ABI and brachial-ankle PWV were measured in 472 consecutive subjects who subsequently underwent coronary angiography for diagnosis or exclusion of CAD. The prevalence of CAD in the lowest ABI quartile was higher than those in the other 3 ABI quartiles, whereas the prevalence in the lowest brachial-ankle PWV quartile was lower than those in the other 3 brachial-ankle PWV quartiles. A multivariate logistic regression analysis demonstrated that the lowest ABI quartile was a significant independent variable for the prevalence of CAD and that the lowest brachial-ankle PWV quartile was a significant independent variable for the absence of CAD in a population. Thus, a low ABI is an independent marker for an additive risk of CAD, whereas a low brachial-ankle PWV may be used as an independent marker for excluding the risk of CAD among subjects with a high risk of atherosclerotic cardiovascular disease.

Published
2004

12. A Case of Complete Thrombotic Occlusion by Endovascular Stent Grafting for Anastomosis Leakage after Aortic Arch Replacement of Stanford Type A Dissecting Aortic Aneurysm

Author

Mikio Ishikawa, Yoshihiko Yokoi, Taro Shimazaki, Hiroaki Ichihashi, Yukio Obitsu, Shin Ishimaru, Hiromi Yano, and Satoshi Kawaguchi

Subjects
medicine.medical_specialty, Thrombotic occlusion, business.industry, medicine, Aortic arch replacement, Radiology, Stent grafting, Anastomosis, business, Dissecting aortic aneurysm, Surgery
Abstract

症例は60歳女性. 突然の胸背部痛で発症した早期閉塞型 Stanford A型大動脈解離と診断され, 保存的治療を行っていた. 発症後約2カ月で再び胸背部痛が出現し, 解離腔の再開通と診断され, elephant trunk を併用した弓部全置換術を行った. 術後のDSAにて, 人工血管末梢吻合部より解離腔へ造影剤の漏出を認め, 1カ月後にステントグラフト内挿術を施行した. 解離腔は血栓化し早期離床が可能であった.

Published
1999

13. Carotid Artery Disease in Patients with Arteriosclerosis Obliterans or Aortic Aneurysm

Author

Takashi Uchino, Mikihiko Itho, Hisahito Takae, Shin Ishimaru, Susumu Makimura, Hiroyuki Fukushima, Hiroaki Ichihashi, and Yoshihide Yao

Subjects
Aortic aneurysm, medicine.medical_specialty, Arteriosclerosis obliterans, business.industry, Internal medicine, Carotid artery disease, medicine, Cardiology, In patient, medicine.disease, business
Abstract

閉塞性動脈硬化症 (ASO) や大動脈瘤における頸動脈病変を評価するために超音波断層法を用い, 頸動脈病変の合併率を中心に検討した. ASOでは85例中74例 (87.1%), 大動脈瘤では57例中37例 (64.9%) と高率に頸動脈病変を合併していた. 頸動脈病変症例の過半数は両側性であった. 頸動脈病変の合併率に年齢および男女差はとくに認めなかった. ASOでは Fontaine 分類や病変部位別における頸動脈病変の合併率に有意差はなく, 大動脈瘤でも胸部瘤と腹部瘤とで有意差はなかった. 頸動脈の病変部位は内頸動脈に最も多く, 脳CT検査の検討では正常症例にくらべ梗塞症例では高率に頸動脈病変を合併していた. ASOや大動脈瘤では, 高率に頸動脈病変を合併していることから脳梗塞を併発する可能性が高いと考えられ, 術前の頸動脈病変の評価が重要であるとともに, 今後の頸動脈病変を合併した症例に対する治療法の検討が重要である.

Published
1998

17. Phase separation in mixed monolayers of poly(.GAMMA.-methyl l-glutamate) and triolein

Author

Masayuki Nakagaki and Hiroaki Ichihashi

Subjects
Phase transition, Chromatography, Chemistry, Analytical chemistry, General Chemistry, General Medicine, Surface pressure, Solvent, chemistry.chemical_compound, L glutamate, Phase (matter), Drug Discovery, Monolayer, lipids (amino acids, peptides, and proteins), Triolein
Abstract

Mixtures of triolein and poly (γ-methyl L-glutamate) (PMLG) were spread on a water-air interface from a helix-favoring solvent and surface pressure-mean area curves were obtained with a surface balance of horizontal float type. The mixtures separated into two or three surface phases at almost all compositions. At relatively low surface pressures, two surface phases, one rich in PMLG and the other rich in triolein, co-existed and at 7 mN/m both changed to a unique duplex film consisting of equi-area PMLG and triolein phases. This duplex film was broken up at 23.5 mN/m. In this system several other phase equilibria between three surface phases were shown.

Published
1987

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